Puncher

ABSTRACT

In a puncher, with respect to a cylindrical cover with a one-end opening hole, a piercing punch is loosely but not movably inserted. A tip end surface of the piercing punch is protruded out from the one-end opening hole of the cover. A cylindrical stripper provided between the cover and the piercing punch is provided detachably from the one-end opening hole. By a biasing member, the stripper is protruded out from the one-end opening hole more than the piercing punch does. When the stripper is pressed in against biasing force of the biasing member, the tip end surface of the piercing punch becomes to protrude out from a through-hole formed at a protruding end of the stripper. A removal-prevention member which prevents the stripper from removing from the cover is provided detachably with respect to the cover.

FIELD OF THE INVENTION

The present invention relates to a puncher for piercing a workpiece with a piercing punch while a stripper is pressing the workpiece.

BACKGROUND OF THE INVENTION

A conventional piercing puncher is disclosed, for example, in Japanese Patent Application Laid Open No. 2006-61938 (refer to FIG. 3).

This puncher 9 is illustrated in FIG. 17 and includes a cylindrical cover 90 with a one-end opening hole 90 a, a piercing punch 91 a tip end of which is protruded from the one-end opening hole 90 a and which is loosely but not movably inserted with respect to the cover 90 by means of a punch retainer 94, and a cylindrical stripper 92 provided between the cover 90 and the piercing punch 91 in a retaining state, and the stripper 92 is protruded more than the piercing punch 91 is from the one-end opening hole 90 a by a compression coil spring 93 (biasing means). When the stripper 92 is pressed in and down against biasing force of the compression coil spring 93, an end surface 91 a of the piercing punch 91 is protruded out from a through-hole 92 a formed at a protruding end of the stripper 92. In FIG. 17, there are shown a supporting plate 95 attached to the cover 90 with a bolt B1, a positioning pin PN for positioning the puncher 9 with respect to an upper die, and a bolt B2 for attaching the puncher to the upper die.

With this puncher, while the stripper 92 presses the workpiece, the piercing punch 91 pierces the workpiece.

In this puncher 9, therefore, when piercing, the workpiece is pressed only at a minimal portion necessary for piercing, so that the portion to be machined could be made as small as possible and piercing may be done at a lower cost. Furthermore, since the puncher could be downsized, a plurality of adjacent holes may be processed with one puncher.

Generally, in case of punching with a puncher, there are methods for positioning by input of certain numeral values into a computer (hereinafter referred to as a numeral value inputting method) and by visually confirming punching positions (hereinafter referred to as a visual positioning method). And conventionally it is necessary to selectively choose one from two types of punchers depending on a method to be used.

However, providing the above two types of punches leads not only to a higher cost but also a need of maintenance thereof.

And the foregoing puncher 9 has a problem that it is difficult to punch a hole at a position near a corner of the workpiece where adjacent metal plate surfaces form the corner with an angle of from 90 degrees to 95 degrees (in many cases, from 90 degrees to 93 degrees, which holds true hereinafter). This is because a peripheral surface of the cover 90 bumps the metal surface other than the metal surface in which a hole is to be punched.

It would be considered to make a diameter of the cover 90 smaller in order to solve the above-described problem. However, this reduces elastic resilient force of the compression coil spring 93 within the cover 90 and then would cause another problem that a pressing force onto a predetermined workpiece cannot be guaranteed.

Further, it would be considered to make the cover 90 with a rubber material and piercing process is conducted while an outer peripheral surface of the cover is pressed against the metal plate surface by utilizing elastic deformability of the rubber. However, this will extremely shorten a lifetime of the cover 90.

Recently, in the industry using a piercing puncher is a demand that one type of a puncher applicable both for the numeral value input method and the visual positioning method becomes available in the market. And there is a further demand for development of a puncher which has a long lifetime, guarantees sufficient pressing force onto a workpiece, and punches a hole at a position near a corner of a workpiece having adjacent metal plate surfaces forming an angle of from 90 degrees to 95 degrees at the corner.

SUMMARY OF THE INVENTION

Therefore, it is an object of the present invention is to provide a puncher applicable both for the numeral value input method and the visual positioning method.

It is another object of the present invention is to provide a puncher which has a long lifetime, can guarantee sufficient pressing force onto a workpiece, and punch a hole at a position near a corner of a workpiece where adjacent metal plate surfaces form a corner with an angle of from 90 degrees to 95 degrees.

The puncher according to the present invention includes a cylindrical cover with a one-end opening hole; a piercing punch, a tip end of which is protruded from the one-end opening hole and which is loosely but not movably inserted with respect to the cover; a cylindrical stripper provided between the cover and the piercing punch in a way that the stripper is pullably removed from the one-end opening hole; and a biasing member by which the stripper protrudes out from the one-end opening hole more than the piercing punch does. When the stripper is pressed in against biasing force of the biasing member, the tip end surface of the piercing punch becomes to protrude out from a through-hole formed at a protruding end of the stripper. And a removal-prevention member which prevents removal of the stripper from the cover is provided detachably as to the cover.

A ring member may be provided between the biasing member and stripper.

The puncher of the present invention also includes a shaft member at the tip face of the piercing punch which protrudes out from the stripper. A punched-out sheet piece remaining within the stripper is pushed out from the stripper by the shaft member.

The biasing member may be made of a compression coil spring.

In the puncher of the present invention, after the removal-prevention member and then the stripper are removed from the cover, the tip portion of the pierce punch protrudes out from the cover, which allows to facilitate the positioning of the piercing punch.

The puncher according to the present invention includes a cylindrical cover with a one-end opening hole; a piercing punch, a tip end of which is protruded from the one-end opening hole and which is loosely but not movably inserted with respect to the cover; a cylindrical stripper provided between the cover and the piercing punch in a retaining state; and a biasing member by which the stripper protrudes out from the one-end opening hole more than the piercing punch does. When the stripper is pressed in against biasing force of the biasing member, the tip end surface of the piecing punch becomes to protrude out from a through-hole formed at a protruding end of the stripper. The cover is made of metal, and a diameter of a cover portion at and near the one-end opening hole is smaller than that of the other cover portion.

In the puncher according to the present invention, the biasing member is received in the foregoing other cover portion. Thus the cover portion at the one-end opening hole side is made smaller than the other cover portion receiving the biasing member.

The cover portion of the one-end opening hole side gradually reduces its diameter toward the opening hole side to form a tapered portion.

And an inclined line of the tapered portion of the puncher of the present invention forms a concave inwardly.

The biasing member of the puncher of the present invention may be a compression coil spring.

Piercing process with the puncher according the present invention is conducted with a piercing punch while a workpiece is kept pressed by the stripper.

The puncher according to the present invention is usable both for a numeral value inputting method and a visual positioning method. The puncher can also provide a long lifetime, guarantee sufficient pressing force onto a workpiece, and punch a hole at a position near a corner of a workpiece having adjacent metal plate surfaces forming an angle of from 90 degrees to 95 degrees at the corner.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an external perspective view of a puncher according to Embodiment 1 of the present invention.

FIG. 2 is a cross-sectional view of the puncher

FIG. 3 is a top plan view of the puncher.

FIG. 4 is an external perspective view of the puncher in the state where a stripper is pressed in from the state shown in FIG. 1.

FIG. 5 is a cross-sectional view of the puncher in the state where the stripper is pressed in from the state shown in FIG. 2.

FIG. 6 is an external perspective view showing the state where a removal-prevention member is removed from the cover and then the stripper is pulled out from the cover.

FIG. 7 is a cross-sectional view of a pierce die using the puncher according to this embodiment, in a top dead center state.

FIG. 8 is a cross-sectional view of the pierce die in FIG. 7 in a bottom dead center state.

FIG. 9 is a cross-sectional view of the pierce die using the puncher, in a top dead center state, where the removal-prevention member is removed and the stripper is pulled out.

FIG. 10 is a cross-sectional view of the pierce die of FIG. 9 in the top dead center state.

FIG. 11 is an external perspective view of a puncher according to Embodiment 2 of the present invention.

FIG. 12 is a cross-sectional view of the puncher in FIG. 11.

FIG. 13 is an external perspective view of the puncher in the state where a stripper is pressed in from the state shown in FIG. 11.

FIG. 14 is a cross-sectional view of the puncher in the state where the stripper is pressed in from the state shown in FIG. 12.

FIG. 15 is a front sectional view of a pierce die using the puncher according to Embodiment 2, in a top dead center state.

FIG. 16 is a front sectional view of the pierce die in FIG. 15 in a bottom dead center state.

FIG. 17 is a cross-sectional view of a conventional puncher.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

Hereinafter, preferred embodiments of a puncher according to the present invention will be described in detail.

Embodiment 1

A puncher according to Embodiment 1 of the present invention is shown in FIGS. 1 to 10. The puncher P, as shown in FIGS. 1 and 2, includes a cylindrical cover 1 with a one-end opening hole 10; a piercing punch 2, a tip end 20 of which is protruded from the one-end opening hole 10 and which is loosely but not movably inserted with respect to the cover 1 by means of a punch retainer 5; and a cylindrical stripper 3 provided between the cover 1 and the piercing punch 2 where the stripper is capable of being pulled out and removed from the one-end opening hole 10 and the stripper 3 protrudes out from the one-end opening hole 10 by a biasing member 4 more than the piercing punch 2 does. When the stripper 3 is pressed in and down against biasing force of the biasing member 4, as shown in FIGS. 4 and 5, the tip end surface 20 is protruded out from a through-hole 30 formed at a protruding end of the stripper 3.

In this puncher, as shown in FIGS. 1 to 5, a removal-prevention member 6 which prevents the stripper 3 from removing out of the cover 1 is provided detachably with respect to the cover 1.

The main elements of the puncher P of the present invention such as the cover 1, the piercing punch 2, the stripper 3, the biasing member 5 and the removal-prevention member 6 are described in detail below.

The cover 1 is made of, for example, carbon steel for machine structural use (S45C), and includes a cylindrical portion 11 and an attaching portion 12 formed in one body with the cylindrical portion 11 at the bottom portion, as shown in FIGS. 1 and 2.

The cylindrical portion 11, as shown in FIGS. 2 and 5, includes a tip end cylindrical portion 11 a mainly receiving the stripper 3, a center cylindrical portion 11 b mainly receiving a compression coil spring 40 serving as the biasing member 4, and a base cylindrical portion 11 c mainly receiving the punch retainer 5. A stepped portion 19 is formed on an inner surface portion between the tip end cylindrical portion 11 a and the center cylindrical portion 11 b of the cylindrical portion 11.

The attaching portion 12 includes, as shown in FIGS. 1, 2 and 5, two bolt insertion holes 13, two positioning pin insertion holes 14, and one screw hole 15. When a bolt 16 is screwed into the screw hole 15, the punch retainer 5 is not removed from the base cylindrical portion 11 c by locking (locking portion k) between the bolt 16 and the punch retainer 5.

Here in Embodiment 1, as shown in FIGS. 1 and 2, the diameter of the cover portion 1 b on the tip end side (where the one-end opening hole 10 is provided) of the cover 1 is made smaller than that of the cover portion 1 a receiving the compression coil spring 40, and the cover 1 gradually reduces its diameter toward the tip end side to form a tapered portion, as shown in FIGS. 1 to 4. The tapered portion is not necessarily required, but it is sufficient to simply make the diameter smaller. In addition, a base point from which the cover 1 reduces its diameter may be somewhat away from a position where the compression coil spring 40 is received.

The piercing punch 2 is obtained by quenching and polishing tool steel and, as shown in FIGS. 1, 2, 4 and 5, is retained by the punch retainer 5 with its tip end surface 20 being located within a through-hole 30 of the stripper 3 by the biasing force of the compressing coil spring 40.

The stripper 3, as shown in FIGS. 2, 5 and 6, has a cylindrical shape capable of being pulled out from the one-end opening hole 10 of the cylindrical cover 1. A ring member 32 is provided between the stripper 3 and the compressing coil spring (the biasing member) 40, with which force of the compression coil spring is reliably applied to the striper 3. The stripper 3 is made of, for example, high strength brass casting (CAC304).

The biasing member 4 is formed with the compression coil spring 40 as described above and shown in FIG. 2, which is a general purpose article and generally and widely available. The biasing member is not limitative to a compression coil spring, but any biasing member may be used as long as it can bias the stripper 3 with a predetermined force.

The punch retainer 5 is made of carbon steel for machine structural use (S55C) and securely fixes the piercing punch 2 within the cover 1.

The removal-prevention member 6 prevents the stripper 3 from being coming out from the cover 1 and is provided detachably with respect to the cover, as shown in FIGS. 1, 2 and 6.

The removal-prevention member 6 includes a fastening plate 60 with an L shape section which has a bolt insertion hole 62 and a positioning protrusion 63; a bolt 61; and a screw hole 17 and a positioning hole 18 provided on a flat wall face 6 a on the cover 1. The positioning protrusion 63 is to be inserted in the positioning hole 18 and the bolt 61 is to be screwed in the screw hole through the bolt insertion hole 62.

In this embodiment, as shown in FIGS. 1 and 6, the cover has a opening H on its upper area and the stripper 3 has a flat part 3 a near its stepped portion. Thus an upper part of the fastening plate 60 is attached to the flat part 3 a through the opening H and thereby the stripper 3 is prevented from rotating with respect to the cover.

In the Embodiment 1, a shaft member 29 is provided on the tip face of the piercing punch 2 and protrudes out from the stripper 3. A punched-out sheet piece remaining within the stripper 3 is pushed out from the stripper 3 by the shaft member 29.

The puncher P is used as described below. FIG. 7 is a cross-sectional view of a pierce die using the puncher according to this embodiment in a top dead center state, and FIG. 8 is a cross-sectional view of the pierce die of FIG. 7 in a bottom dead center.

(1) First, a workpiece W is placed on a workpiece supporting member 70 fixed on a lower die base plate 7, and the puncher P is set on an upper die base plate 8 for piercing the workpiece W. The puncher P is attached to the upper die base plate 8, as shown in FIG. 7, by screwing bolts B inserted in the bolt insertion holes 13 of the attaching portion 12 into the upper die substrate 8, and further by driving pins PN press-fitted in the positioning pin insertion holes 14 into the upper die base plate 8.

(2) In a state where the workpiece W is placed on the workpiece supporting member 70, an upper die 80 lowers down. Then, the stripper 3 comes into contact with the workpiece W, and thereafter, the stripper 3 is pressed in against the biasing force of the compression coil spring 40. Here, an outer peripheral area of the portion to be pierced of the workpiece W is strongly pressed.

(3) When the upper die 80 further lowers down from the above-described state, the piercing punch 2 protrudes out from the stripper 3 and punches a hole in the workpiece W, and the upper die 80 still further lowers down to be in the bottom dead point state shown in FIG. 8.

(4) When punching is completed and the upper die 80 moves back upward, the workpiece W which has been punched and is sticking to the puncher P is separated away from the puncher P due to the stripper 3 biased downward with the compression coil spring 40.

This puncher P has the following advantageous functions and effects.

-   -   (1) In case of punching at the position determined by a         computerized numeral control, as shown in FIGS. 1 and 2, a fully         assembled puncher P is precisely placed on the upper die and the         punching is proceeded according to the way of use of the puncher         P described above.     -   (2) In case of visually determining the punching position, the         bolt 61 is loosened, the fastening plate 60 is detached from the         cover 1, and then the stripper 3 is pulled out from the cover 1.         In this state, since the piercing punch 2 protrudes out from the         cover 1, it is possible to visually position the tip end of the         piercing punch 2 at the position to be punched. Subsequently,         the detached members are re-assembled as in FIGS. 1 and 2, then         a punching operation can be started.     -   (3) The puncher of the present Embodiment can be used with both         the numeral value input method (1) and the visual positioning         method (2) stated above.

Embodiment 2

A puncher of Embodiment 2 of the present invention is illustrated in FIGS. 11 to 16. This puncher P, as shown in FIGS. 11 and 12, includes a cylindrical cover 1 with a one-end opening hole 10; a piercing punch 2, a tip end 20 of which is protruded from the one-end opening hole 10 and which is loosely but not movably inserted with respect to the cover 1 by means of a punch retainer 5; and a cylindrical stripper 3 provided between the cover 1 and the piercing punch 2 in a retaining state, and the stripper 3 protrudes more than the piercing punch 2 does from the one-end opening hole 10 by a biasing member 4. When the stripper 3 is pressed in against biasing force of the biasing member 4, as shown in FIGS. 13 and 14, the tip end surface 20 is protruded out from a through-hole 30 formed at a protruding end of the stripper 3.

Especially, in the puncher P, the cover 1 is made of metal, and a diameter of a cover portion 1 b on a tip end side (where the one-end opening hole 10 is provided) is made smaller than that of a cover portion 1 a receiving the biasing member 4, as shown in FIGS. 11 to 14.

The main elements of this puncher, namely the cover 1, the piercing punch 2, the stripper 3, the biasing member 4, the punch retainer 5 are basically the same as those in Embodiment 1.

In the cover 1, as stated above, the diameter of the cover portion 1 b on a tip end side (where the one-end opening hole 10 is provided) is made smaller than that of a cover portion 1 a receiving the compression coil spring 40. The shape of the small diameter portion is shown in FIGS. 11 to 14, and forms a tapered portion gradually reducing the diameter toward the one-end opening hole. Here it is preferable that an inclined line of the tapered portion is concave inwardly. The tapered portion is not necessarily required, but it is sufficient to simply make the diameter smaller. In addition, a base point from which the cover 1 reduces its diameter may be somewhat away from a position where the compression coil spring 40 is received.

The stripper 3, as shown in FIG. 12, has a cylindrical shape having an peripherally protruding collar portion 31 at a rear end side, and stands in a retaining state with respect to the cover 1 by an engagement between the peripherally protruding collar portion 31 and the stepped portion 19 by biasing of the compression coil spring 40. The stripper 3 is made of high strength brass casting (CAC304), for example.

In Embodiment 2, in order to prevent the stripper 3 from rotating, as shown in FIG. 12, a groove 60 extending in an axial direction is formed on an outer peripheral wall of the stripper 3, and a screw-shaped protrusion 61 provided on an outer wall of the cover 1 protrudes into the groove 60. Such structure is not essential and may be omitted.

The puncher 2 according to Embodiment 2 is used like Embodiment 1 described above. FIG. 15 shows a front cross-sectional view of a pierce die using the puncher of Embodiment 2 in a top dead center state, and FIG. 16 shows a front cross-sectional view of the pierce die of FIG. 15 in a bottom dead center state. This puncher P has the following advantageous functions and effects.

(A) Long Lifetime is Obtainable

An easy solution against the problem in the prior art is, as already described above, to make a cover with a rubber material and do piercing process while pressing an outer peripheral surface of the cover against a metal plate surface making use of elastic deformability of the rubber. However, this solution will raise a problem that the lifetime of the cover is very short.

On the other hand, the puncher P according to the embodiment of the present invention has a very long lifetime since the cover could be made of metal material having high rigidity.

(B) Guarantee of a Sufficient Pressing Force to the Workpiece. An easy solution against the problem in the prior art is to reduce the diameter of the cover. This solution, however, reduces an elastic restoring force of the compression coil spring arranged within the cover and could raise another problem that the predetermined pressing force to the workpiece is not guaranteed.

On the other hand, the puncher P according to the embodiment of the present invention, in which the diameter of the compression coil spring does not have to be smaller, may guarantee the predetermined pressing force to the workpiece.

(C) Easy Punching Near an Angled Corner

In the embodiment of the present invention, the cover 1 is made of metal, and the diameter of the cover portion 1 b at the tip side (where the one-end opening hole 10 is provided) is smaller than that of the cover portion 1 a receiving the compression coil spring 40. The cover 1 reduces its diameter with a tapered portion in which the diameter gradually becomes smaller toward the tip end side, as shown in FIGS. 1 to 4. Providing this cover portion with the reduced diameter facilitates an easy punching near an angled corner.

Specifically, the puncher P according to the present invention is used when punching a hole for fitting rubber materials to be stretched on an inside of an automobile door so as to prevent rain and wind from entering inside of the automobile from outside. Part of a metal plate to be punched generally has a small width, and existence of another metal plate adjacent to it, the two of which form a corner with an angle of from 90 degrees to 93 degrees, makes punching very difficult.

However, in the puncher P according to the present invention, the cover portion 1 b with the reduced diameter facilitates to punch a hole at a position closer to a corner of the metal plate surfaces in a workpiece (see FIG. 16). As a result, holes for fitting rubber materials to be stretched on an inside of an automobile door so as to prevent rain and wind from entering the automobile interior from outside are readily punched.

As to the puncher P of the present application, for example, the following modification can be freely made.

The removal-prevention member 6 of Embodiment 1, as shown in FIGS. 1, 2 and 6, allows not only to make the stripper 3 detachable or undetachable with respect t the cover 1, but also to prevent the stripper 3 from rotating with respect to the cover 1 by making use of part of the structure of the removal-prevention member 6. In another embodiment, the removal-prevention member 6 may function only to make the stripper 3 detachable or undetachable with respect to the cover 1. In this case, another rotation-prevention member may be provided.

Both in Embodiments 1 and 2, the cover 1 and the attaching portion 12 are formed into a single body, but not limitative thereto and they may be made by separate members to be coupled by a bolt. Two bolt insertion holes 13 are provided, but not limitative thereto and one or three of them may be provided upon demanded. The puncher of the above Embodiments punches a round hole, but not limitative thereto and the hole may be in an oval shape, an elliptical shape or other shapes. The puncher P may be mounted on a slide cam die and punch a hole in a workpiece.

The puncher P according to the above embodiment has an extremely downsized structure with an entire length of 72 mm and an attaching portion 12 shaped in a triangle with 32 mm length and 30 mm wide. 

1.-11. (canceled)
 12. A puncher comprising: a cylindrical cover with a one-end opening hole; a piercing punch, a tip end surface of which is protruded from the one-end opening hole, and which is loosely but not movably inserted with respect to the cover; a cylindrical stripper provided between the cover and the piercing punch which is removable from the one-end opening hole; a biasing member by which the stripper protrudes out from the one-end opening hole more than the piercing punch; and wherein, when the stripper is pressed in against biasing force of the biasing member, the tip end surface of the piercing punch protrudes out from a through-hole formed at a protruding end of the stripper, by the pressing of the stripper against the biasing force of the biasing member, the tip end face of the piercing punch protrudes out, a removal-prevention member which prevents the stripper from being removed from the cover is provided detachably with respect to the cover.
 13. The puncher according to claim 12 further comprising a ring member between the biasing member and the stripper.
 14. The puncher according to claim 12, wherein the piercing punch has a shank member on the tip end face thereof which protrudes out from the stripper and a punched-put piece of the workpiece remaining within the stripper is cleared out by the shaft member.
 15. The puncher according to claim 12, wherein the biasing member is made of a compression coil spring.
 16. The puncher according to claim 12, wherein, when the removal-prevention member is removed from the cover and then the stripper is pulled out from the cover, the tip end of the piercing punch is protruding out from the cover so as to allow positioning of the piercing punch.
 17. The puncher according to claim 13, wherein the piercing punch has a shank member the tip end face thereof which protrudes out from the stripper and a punched-put piece of the workpiece remaining within the stripper is cleared out by the shaft member.
 18. The puncher according to claim 13, wherein the biasing member is made of a compression coil spring.
 19. The puncher according to claim 13, wherein, when the removal-prevention member is removed from the cover and then the stripper is pulled out from the cover, the tip end of the piercing punch is protruding out from the cover so as to allow positioning of the piercing punch. 